Jusqu'à vs à?

I feel I don't quite know how to use jusqu'à. IMO, if I say "I walk to my car," it should be "je marche à ma voiture" and if I say "I walk you to your car," then it's "je te marche jusqu'a ta voiture" because I actually get into my car while I only walk with you until you reach your car. I don't get into your car.

Do I understand it correctly? I ask because sometimes I see je marche jusqu'à ma voiture and that confuses me. Does the person just walk to his car and then turn around to go somewhere else? :-) Seems odd.

It's a language! You use it to communicate - you get things wrong, then not-quite-right, then right as you go along - don't beat yourself up! I once heard a French guy say "I am the sailor man, I am sailing in my boat" - he'd been learning English by practising with a small child :)

Basically it's what you said. In short Jusqu'à = as far as (as in to a certain point and STOP) and à = to (and into a certain location e.g. je vais à la plage = I go (in)to the beach). The beach is your final destination and got in there.